Carbon capture and valorization is a new route increasingly discussed to reduce greenhouse gas emissions. One of the paths foreseen for CO 2 valorization is its transformation into fuels by electrochemical reduction of carbon dioxide. In this approach, molten carbonates are of particular interest since they can be used to capture CO 2 molecule because of its high solubility; hence, valorization by electrolysis is possible in molten carbonate media. To better understand CO 2 reduction, chronopotentiometric and chronoamperometric techniques were used at gold and graphite electrodes immersed in four alkali carbonate eutectics, Li-Na, Li-K, Li-Na-K and Na-K. The results complemented a previous work based on cyclic voltammetry and confirmed the existence of a main CO 2 reduction phenomena around −1.2 V vs Ag/Ag + that involves two one-electron steps or a two-electron unique step. Transition time analysis showed that the reduction mechanism is either simultaneous reduction of CO 2 adsorbed and diffusion species or rapid equilibrium between adsorbed and diffusing species. Furthermore, we identified another electrochemical system involving adsorbed CO 2 and CO at higher potentials. In summary, we have succeeded in proving and précising some previous results, as well as identifying reduction mechanisms.

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